Dateline 1941: Did the Martin Baltimore have any advantages over the Douglas A-20 Havoc sufficient to justify US adoption?

[Conslaw]

Martin built 1,575 Baltimore bombers, and they received a lot of combat service by air forces other than the United States. None were saved, so the type has faded into history. Still, it was very similar in capabilities to the Douglas A-20 Havoc ("Boston" in UK and USSR service). Make the case for your favorite plane. If you really want to blur things, you can throw the Lockheed Ventura into the mix. We've discussed the B-25 and B-26 to death, so let's try to keep them in the background in this thread.

 

[Shortround6]

Timing for one thing.
A-20s were coming off the production line in late 1940, First flight by Baltimore prototype was June of 1941.
A-20 was almost 40mph faster.
A-20 had less range (at least early versions)

You may have to bring the B-25 into it (at least early ones) as the Baltimore was sort of in-between the A-20 and B-25 as far as weight and wing area go and the Baltimore was designed for a 4 man crew from the start. A-20s used 3-4 men depending on if they carried a 4th man for the lower fuselage gun.

All three planes used R-2600 engines.

 

[muskeg13]

At the risk of being shot to pieces for diverting a bit from the opening theme, I don't see the Baltimore offering any significant improvement over the earlier and under-appreciated Maryland.

The Maryland (Martin Model 167) was in direct competition with the Douglas DB-7 (A-20), but came in second in the 1938-1939 USAAC competition. Trying to juggle specs between what Wiki and Joe Baugher's site offer, the Maryland had several attributes where it may have bested the A-20, but a lot depends on which model A-20 you're trying to make the comparison with. It appears the Maryland had better range (1300 mi vs. about 1000 mi), better rate of climb (2400 fpm vs. 2000 ft/min), and may have been a bit more nimble with a lower wing loading, with 1100 less total HP.

Assuming the slight advantages are true, would this justify U.S. adoption? It didn't historically, and the speed advantage in the earlier/lighter A-20s was significant. I'd guess there would need to be a problem in the USAAC getting the numbers of aircraft it needed within the required timeframe. If more light attack bombers were needed, the Maryland would have made a decent substitute standard.

 

[Conslaw]

At the risk of being shot to pieces for diverting a bit from the opening theme, I don't see the Baltimore offering any significant improvement over the earlier and under-appreciated Maryland.

The Maryland (Martin Model 167) was in direct competition with the Douglas DB-7 (A-20), but came in second in the 1938-1939 USAAC competition. Trying to juggle specs between what Wiki and Joe Baugher's site offer, the Maryland had several attributes where it may have bested the A-20, but a lot depends on which model A-20 you're trying to make the comparison with. It appears the Maryland had better range (1300 mi vs. about 1000 mi), better rate of climb (2400 fpm vs. 2000 ft/min), and may have been a bit more nimble with a lower wing loading, with 1100 less total HP.

Assuming the slight advantages are true, would this justify U.S. adoption? It didn't historically, and the speed advantage in the earlier/lighter A-20s was significant. I'd guess there would need to be a problem in the USAAC getting the numbers of aircraft it needed within the required timeframe. If more light attack bombers were needed, the Maryland would have made a decent substitute standard.

Like the Martin 167 Maryland, the Douglas DB-7 Boston used Pratt and Whitney R-1830 engines. The Martin 187 Baltimore and the Douglas A-20 upgraded to Wright R-2600 engines. So, as I understand it, the US didn't buy either plane with R-1830 engines, but bought the Douglas plane once it had R-2600s. By appearances, the Martin plane changed more with the engine swap. It also seems that the A-20 went into production with R-2600s slightly ahead of the Martin Baltimore. We are talking a few months. But in 1940-1941, a few months make a big difference.

 

[fastmongrel]

Only thing I can add. The Baltimore according to pilots memoirs was a bit of a handful taking off and landing. In the air the Baltimore was fine pilots liked the handling and it seemed to be very accurate as a level bomber which was it's normal use in RAF and SAAF service.

 

[Schweik]

Timing for one thing.
A-20s were coming off the production line in late 1940, First flight by Baltimore prototype was June of 1941.
A-20 was almost 40mph faster.
A-20 had less range (at least early versions)

You may have to bring the B-25 into it (at least early ones) as the Baltimore was sort of in-between the A-20 and B-25 as far as weight and wing area go and the Baltimore was designed for a 4 man crew from the start. A-20s used 3-4 men depending on if they carried a 4th man for the lower fuselage gun.

All three planes used R-2600 engines.

Which specific versions are you comparing for speed here?

 

[Schweik]

All three aircraft - Boston (both DB-7 and A-20 types), Maryland, and Baltimore were in fairly heavy use in the Med at the same time, though a bit overlapping as Maryland was gradually phased out as a bomber in favor of the Baltimore. The Baltimore and Boston were both fairly heavily modified, especially in terms of armament, though capabilities were similar as level bombers. The Mitchel / B-25 came in to action fairly late in the game, as did the B-17 and B-24 heavy bombers.

Their other main competition on the Allied side was the Blenheim, which was largely phased out pretty early on.

Here are some facts I know:

Boston was quite fast (up to 310 mph in some configurations, more in the later war versions but those were too late for action in the med). I think (only based on anecdotal comments by pilots) it was the fastest of the three down near sea-level, but not by much.
Boston / A-20 was used quite effectively in the anti-shipping role in the Med with mast-height bombing techniques and sunk some ships close to shore.
Some versions of the Boston were more heavily armed with nose guns (often added in the field) for use as low-level 'strafers', though due to effective German AAA, they took heavy losses and this strafing strategy was somewhat curtailed as compared to the Pacific. It was also used in Maritime strikes to supress flak on the ships.
Boston was considered a bit cramped by crew, as were the Maryland and Baltimore, but the narrow fuselage also contributed to their speed.
They trained in Bostons as a night fighter but I don't know if it was ever used as such in the MTO.
Had a moderately high loss rate. It was not unusual if you read through the raids in MAW that they would lose 1 or 2 on a raid of 10-20 bombers.
Had somewhat short range (~900 miles).

Maryland was quite fast (up to about 300 mph) with a pretty good 'typical' cruise speed (over 250 mph)
Was considered agile and even used as a fighter against enemy maritime aircraft (had 4 forward firing .303 guns). There was at least one ace who scored at least five victories flying Marylands (mostly against enemy sea planes etc.). The same guy also flew the recon missions prior to the famous Taranto raid in his Maryland.
Seemed to carry a lighter bomb load in practice than the Baltimore or the Boston (often only carrying 2 bombs).
Was lightly armed and (so far as I know) never up-gunned (defense was from Vickers K guns).
Pretty good range (~1200 mile).
Had a moderate loss rate which became higher until it was phased out for over-land strikes.
Ended up being used in the maritime and high speed recon role after being supplanted as a bomber over the intensively contested land war.

Baltimore was quite fast (305 mph) but had a lower cruise speed than the Maryland.
Also had an exceptional dive speed, and was used for post-war testing of supersonic flight rather amazingly.
It was very difficult / tricky to takeoff requiring perfect coordination of throttles.
Once in the air it was considered agile, almost as much as the Maryland.
Like the Maryland it had four wing mounted .303 guns, (but no nose mounted guns like the Boston).
Had a fairly high loss rate initially when used sporadically and often on unescorted missions.
Ended up with the lowest loss rate of all bombers on the Allied side once flown in better planned (and better escorted) missions later in the war.
Fairly short range (~1,000 miles) depending on load.
Was up-gunned with dorsal .303 being replaced by a turret with two .50 cals.
Was used in bombing operations by the British until the capitulation of Italy.

All three had a fairly low bomb load, with both A-20 and Martin 187 / Baltimore carrying about 4 x 500 lb bombs on most missions, while Maryland often only carried two.
Bombing was pretty accurate though, and all three twin engined types were considered more effective against operational targets like airfields, ports, and supply dumps etc. than the fighter bombers were.
Baltimore seemed to be the best at escaping / contending with Axis fighters, and their raids usually caused substantial damage. After their raid they would go into a shallow high speed dive to escape the battle area.
Boston was the most effective strafer and maritime strike aircraft.
Maryland had the best range and seems to have been the most effective in the fighter role.
All three were basically low to medium altitude aircraft; fast, pretty agile, light bombers. Less heavily armed than the later Allied day bombers.


B-25 carried up to 6 x 500 lb bombs, and B-24 up to 16 of them, and the latter two seemed to have done the most to pulverize Axis basis, though they took significant losses, and that was after Allied air cover was at it's maximum level. So I think they proved more decisive but the Baltimore seemed to be the best suited for the higher threat environment.

 

[GreenKnight121]

The USAAF also wanted Martin building B-26 Marauders, not Marylands or Baltimores.

 

[Schweik]

And yet they did continue making Baltimores, which remained in use by some Commmonwealth units right up to 1945. (454 and 459 RAAF, 125 SAAF, and 500 RAF for example) with numerous RAF and Commonwealth units using them through 1944. The original French order was for 400, with the British ordering two more batches of 575 and 600. B-26 production was of course much greater (over 5000).

The B-26 was far more heavily armed, and carried roughly double the bomb load.

But I think the fast, nimble Baltimore was quite a good warplane and is one of the underrated types of the war. I'm not sure the B-26 (or any other Allied type) could have done better in the same niche early on in the Med.

 

[tomo pauk]

Boston was quite fast (up to 310 mph in some configurations, more in the later war versions but those were too late for action in the med). I think (only based on anecdotal comments by pilots) it was the fastest of the three down near sea-level, but not by much.
Boston / A-20 was used quite effectively in the anti-shipping role in the Med with mast-height bombing techniques and sunk some ships close to shore.

A-20 was faster in earlier versions - 340+ mph; later versions were slower due to greater weight and drag. (link)
Neither Maryland nor Baltimore were 'quite fast' for the air war of 1941 and on. Not with ~300 mph top speed.

 

[Schweik]

Well, I mean they were 'quite fast' compared to other contemporaneous bombers active in the Theatre, and notably so at the (fairly low) altitudes they were flying.

They were faster than SM. 79, SM. 84, CANT Z.1007, He 111, Blenheim, Beaufort, Ju-88A, B-26, or B-25 for example.

~300 is decent speed for a bomber, it's not just about battling it out with fighters, it's also a matter of how quickly they can exit the battle area after dropping their bombs, how easy they are to intercept etc. 340 mph is very good speed for a twin engined bomber in that period of the war I'd say. I'd love to know if any of the DB-7/ A-20 aircraft operational in the MTO could make that speed.

And as you know, top speed at optimal altitude isn't the only measure. When it comes to the Baltimore they were apparently making much better than 300 in shallow dives after dropping their bombs.

Here is a pretty good article on operational history The Forgotten Bomber: The Martin A-30 Baltimore

 

[tomo pauk]

Well, I mean they were 'quite fast' compared to other contemporaneous bombers active in the Theatre, and notably so at the (fairly low) altitudes they were flying.

They were faster than SM. 79, SM. 84, CANT Z.1007, He 111, Blenheim, Beaufort, Ju-88A, B-26, or B-25 for example.

~300 is decent speed for a bomber, it's not just about battling it out with fighters, it's also a matter of how quickly they can exit the battle area after dropping their bombs, how easily they are to intercept etc. 340 mph is very good speed I'd say. I'd love to know if any of the DB-7/ A-20 aircraft operational in the MTO could make that speed.

After 1940, a bomber that goes ~300 mph is very easy to intercept for Luftwaffe, that are flying 370+ mph fighters.
DB-7 (ie. the ones powered by R-1830s) were around 300 mph - very good value for 1940 indeed. Maryland was thereabout. Both flew sorties with low loss rates in the FAF service in 1940.

 

[elbmc1969]

At the risk of being shot to pieces for diverting a bit from the opening theme, I don't see the Baltimore offering any significant improvement over the earlier and under-appreciated Maryland.

The Maryland (Martin Model 167) was in direct competition with the Douglas DB-7 (A-20), but came in second in the 1938-1939 USAAC competition. Trying to juggle specs between what Wiki and Joe Baugher's site offer, the Maryland had several attributes where it may have bested the A-20, but a lot depends on which model A-20 you're trying to make the comparison with. It appears the Maryland had better range (1300 mi vs. about 1000 mi), better rate of climb (2400 fpm vs. 2000 ft/min), and may have been a bit more nimble with a lower wing loading, with 1100 less total HP.

Assuming the slight advantages are true, would this justify U.S. adoption? It didn't historically, and the speed advantage in the earlier/lighter A-20s was significant. I'd guess there would need to be a problem in the USAAC getting the numbers of aircraft it needed within the required timeframe. If more light attack bombers were needed, the Maryland would have made a decent substitute standard.

I agree, you have to start with comparing the Maryland and the DB-7/early A-20.

After that, you have to make a timeline to see how each plane has developed to that date, extending it with the Baltimore.

I'd stop the stop the comparison before the A-26 comes on the scene, since it's in another category entirely.

 

[Schweik]

It seems to me like neither the Douglas DB-7/ A-20 nor the Martin 167-187 series would have gotten far if it weren't for British / French purchasing commission and subsequent British interest. And that is where they excelled the most, in British use. DB-7 and Martin 167 showed their usefuleness in Battle of France, and the Russians got some mileage out of the DB-7 as well, but I think the British did the most damage with them. The US seemed to be lukewarm on the A-20 at first, but the British liked it and influenced it's development. Maryland and Baltimore wouldn't have been developed at all if not for foreign orders. Development was also influenced by the foreign customers.

In both cases, I would say it was in Allied - especially British hands that both bombers had the most telling effect in the war. The US had a different set of priorities and didn't really see the need for bombers in this specific niche, but once they were available (as the A-20) they did prove useful. The Baltimore would have probably been useful too in the Pacific Theater, but it was in a slightly different niche.

 

[Shortround6]

I think you need to research the A-20 a bit more.

We at least need to figure out where the DB-7 stops and the A-20 begins

as for

The Russians got some mileage out of the DB-7 as well, but I think the British did the most damage with them.

By the end of the war, 3,414 A-20s had been delivered to the USSR, 2,771 of which were used by the Soviet Air Force.

This is out of 7,478 built in total. At some points during the war the USSR had more A-20s than the US did.

The US ordered 186 A-20s in June of 1939, these were all powered by Wright R-2600s of several different models. Deliver took a while but the US order was not influenced by user reports by either the French or British.
The US ordered 999 A-20Bs in Oct of 1940, again showing US interest without benefit of much in the way of user reports from either France or Britain. This was a bit of a panic buy as the planes were not equipped with armor or self sealing tanks and thus, only a percentage saw service with the US forces. 665 of them were sent to the USSR.

The US never got any production DB-7s/A-20s with P&W R-1830s.

US interest in the Martin Baltimore has to take into account the B-25 Program.
The US issued an order for 184 B-25s on Aug 10th 1939 although final approval took until Sept 10th 1939 (same date the US placed initial order for Martin B-26 bombers).

The first French Martin 167 (Maryland) flew in Aug 1939. The British wound up with about 125 Maryland Is (50 ?) ex-French and 75 British ordered and a further 150 Maryland IIs.

The Martin 187 (Baltimore) was not ordered by a French/British purchasing commission until May of 1940. (400 planes) which is a bit late for the USAAC to decide to cancel the B-25.

 

[Schweik]

I think you need to research the A-20 a bit more.

We at least need to figure out where the DB-7 stops and the A-20 begins

as for




By the end of the war, 3,414 A-20s had been delivered to the USSR, 2,771 of which were used by the Soviet Air Force.

This is out of 7,478 built in total. At some points during the war the USSR had more A-20s than the US did.

They did have a lot of them, but they were mostly used in the Baltic in the anti-shipping role. They caused some harm to Axis interests, but took very heavy losses (those first 665 without self-sealing fuel tanks or armor probably didn't help). The Soviets did like them and got some good use out of them, there used to be a good article about their use of the 'Boston' on that Leand-lease.ru site a while back. But from what I gather it did not have a major impact on the ground war or 'frontal operations' as the Soviets called it, whereas I would say that the DB-7 and A-20 did play a significant role in North Africa.

In the Pacific the fighting was on a somewhat smaller scale but the A-20 (actually redirected and converted DB-7s intended for France) did play an important role there as well, particularly under Kenneys 5th AF, helping to defend New Guinea in the heavy fighting there in 1942. They were being used alongside B-25s in the Pacific in later years, right up to the end of the war.

The US ordered 186 A-20s in June of 1939, these were all powered by Wright R-2600s of several different models. Deliver took a while but the US order was not influenced by user reports by either the French or British.
The US ordered 999 A-20Bs in Oct of 1940, again showing US interest without benefit of much in the way of user reports from either France or Britain. This was a bit of a panic buy as the planes were not equipped with armor or self sealing tanks and thus, only a percentage saw service with the US forces. 665 of them were sent to the USSR.

The US never got any production DB-7s/A-20s with P&W R-1830s.

US interest in the Martin Baltimore has to take into account the B-25 Program.
The US issued an order for 184 B-25s on Aug 10th 1939 although final approval took until Sept 10th 1939 (same date the US placed initial order for Martin B-26 bombers).

The first French Martin 167 (Maryland) flew in Aug 1939. The British wound up with about 125 Maryland Is (50 ?) ex-French and 75 British ordered and a further 150 Maryland IIs.

The Martin 187 (Baltimore) was not ordered by a French/British purchasing commission until May of 1940. (400 planes) which is a bit late for the USAAC to decide to cancel the B-25.

I certainly wouldn't see cancelling either the DB-7 / A-20 or the B-25 (or B-26) but they did build some more Baltimores, as I mentioned, more or less to British specs. But I'm sure General Kenney could have found a use for a few hundred himself.

 

[Greg Boeser]

Not necessarily. In the Pacific, both the B-17 and B-26 were phased out in favor of the B-24 and B-25 to simplify supply issues. Kenney also was lukewarm on the A-26, preferring to stick with the B-25s and A-20s he already had. Adding another type with it's attendant supply issues would seem against form.

 

[Schweik]

Well they (5th AF) evaluated the A-26 and had a specific beef with it, to do with lateral visibility. And that was a bit later in the game I think. But you do have a point about simplifying supply lines. I was never really clear why the B-26 was phased out in the PTO. B-24 did seem like the better fit as far as the heavies.

 

[Greg Boeser]

I see a number of motivations to pull the B-26 from the Pacific theater.
1. In mid-1942 the design was being reworked to accommodate a larger wing to address the poor take off and landing performance. B-25 production quickly surpassed B-26 production.
2. The heavier B-26 was hoped to be more survivable in the skies over Europe and all Europe bound USAAF medium bomb groups were to be equipped with the B-26.
3. The B-25C and D with additional wing tankage had superior range compared with the larger, heavier B-26B.
4. B-25s were proving more adaptable to modification as strafers.

 

[GrauGeist]

B-24 did seem like the better fit as far as the heavies.

Even though the B-17 had better survivability, the B-24 became prominent in the PTO after late 1943/early 1944.

Oddly enough, it was the B-17 that became the eminant recon/SAR platform in the PTO, it's rescue configuration being used for many years after the war.